Method of freeing and extracting castings from molds



Aug. 26, 1930. L. A. CAMEROTA METHOD OF FREEING AND EXTRACTING CASTINGS FROM MOLDS Filed Sept. '7. 1929 2 Sheets-Sheet l g- 1930. L. AQCAMEROTA 1,774,082

METHOD OF F REEING AND EXTRACTING CASTINGS FROM MOLDS Filed Sept. 7, 1929 2 Sheets-Sheet 2 INVENTOR: Louis .6. Camemia,

TORNEYS.

WITNESSES ggwww Patented Aug. 26, 193i) UNITED STAT-ES PATENT *oFFrcE :LOUIS A. CAMEROTA, 0F BURLINGTON, NEW JERSEY, AS SIGNOR 'IlO WALTER WOOD,.

' OF PBJZLADELPHIA, PENNSYLVANIA.

mn'rI-Ion or rnnnmo AND nxrnncrme casrmcs mom MoLns Application filed September "7, 1929. Serial No. 390,986.

My invention relates to the art-of freeing and extracting a casting from a flaskv lined with a refractory mold, and has particular reference to a method ofv thus freeing and extracting hollow metal bodies, such as pipes which have been cast centrifu ally, from sand linedfiasks of .the unitary c osed ye-j."--

v i 11 pipes are frequently cast with a bell 1'6 shaped flange at one end and a bead at the other end. When cast by the centrifugal process in a closed flask, such a pipe cannot be freed from its mold by mechanical appliances exerting a-pull or push upon the ipe and tending to inove it relative tothe ask without the danger of damagingeither flask 0r"ca'sting.- This is so because, as the bell end' is drawn from the flask, the beadcompresses the moldahead of it so that the pipe y'b'ecomes jammed in the mold. Even with plain cylindrical castings on which there is no bead, an attempt'to force the castingthroughtheflask results in further compressingthe mold, the pressure increasing as the casting pro ssed. Here't'ofore several methods have en proposed by whichthe sand lining may be disintegrated to makepossible thefremoval of the pipe castin from ltsflaskb One such metho is to she e out jecting the flask to a succession of violent jars on a vibrating machine. While it is possible in this manner to free a casting from its mold, the time ex nded in the operation, thelabor in hfid ing the flask, and the danger of damaging the flasks are suchthat .a quicker, more'eflicient and 'more economical 'method is desirable.

been devised for cutting out the sand mold e by mechanical cutters, and while: apparatus of this type possesses advantages over, the .1 'arring ]ecting om the casting'into the sand mold, these scabs prevent-fthe proper operationof. s45

ly difiicult to remove the casting. tracting pipe castings from close fl the above methods, and, so far as I am aware, by all other methods now practiced, the sand .60 lining is disintegrated by the removal of rocess, where there are scabs prothe mechanical'cutters and render it exF'eme- I1 exthe molded sand lining from its flask by sub-' Means have alsoasks by grating a portion of the mold or lining by boring the same to eflect a longitudinal slot substantially throughout its length at one or more points to free the casting to such an extent that pressure thereafter applied to the casting can force it through the flask without its jamming in the mold. My invention is particularly applicable to freeing pipe castings which are extremely diflicult to remove by other methods and is adapted to be used as a preliminary operation prepara-- tory to a mechanical stripping of a casting from its flask.

For a better understanding of the invention, its objects and specific advanta 'es obtained-with its use, reference should be had to the accompanying drawin s and descriptive matter, in which I have lllustrated and described one embodiment of the invention.

Of the drawings:

Fig.1 shows a side elevation of apparatus em loyed for freeing a pipe casting from a close flask according to the manner of my invention.

' Fig. II shows'a longitudinal cross-section of a flask and pipe casting in position for the first stepof the stripping apparatus.

Fig. III shoWs atransverse section of the same taken along thelines III-III of Fig. II} and Fi IV V is a detailed view of a standard for guiding an air nozzle into the mold of a flask. v v c For'convenience I have illustrated in Fig. I a shed 1 constituting a station to which flasks 2 are brought from a centrifugal casting machine by rolling them along rails 3. At this station the flasks are momentarily halted for the application of the first step ofa strippingoperation. The flasks 2 are of the customary unitary type used in makingpipe castings by the centrifugal process and are provided wlth perforations 27 which permit the escape of foundrygases during in their proper positioning for the applica tionof the first step of the stripping operation. I

A hood 5 serving as a dust collecting enclosure is shown surrounding the flask 2. To admit the flask within the hood, horizontal hinged doors may be provided in an obvious manner at the points where the rails 3 enter and leave the enclosure. Preferably located in a pit 6 beneath the hood 5 there is provided an exhaust fan or blower 7 operated by a motor 8 and having one or more exhaust trunks 9 leading from the hood 5 to the blower 7. However, the dust collecting enclosure and the means for exhausting it are not essentially a part of the invention, but are merely illustrated as a convenient method of reducing flying dust and fine sand incident to the operation of the apparatus.

At one side of the flask station I provide a movable platform' or car 10 preferably equipped with its own motor and speed reducer diagrammatically shown at 11 and adapted to travel back and forth on tracks 12 which parallel the longitudinal axis of the flash 2. Mounted on the forward end of the car 1.0 is a support 13 for rigidly holding a blow pipe 14 and having therein a connection joining a flexible air hose 15 with the blow pipe 14. The flexible air hose 15 is in turn Iii/connected with a compressed air line 16 equipped with a valve 17 at a convenient point. To keep the flexible air hose 15 off the floor of the shed 1 while the car is moving, I prefer to use a Weight 18 with a cord 19 attached to the hose and suspended by pulleys 20 from the roof of the shed.

The blow'pipe 14 and its nozzle 25 are guided toward the sand mold 21 of the flask 2 by means of a standard 22 adjacent 'the end of the flask 2. The standard 22 is provided with an opening 23 permitting the passage therethrough of the blow pipe '14 and directing it into the mold at the proper level. To maintain the flask 2 in. alignment with the blow pipe 14, I may use any well-known mechanical ap liance acting as a stop in the path of the asks along the rails 3. For this purpose, there are shown (see Fig. III) notched centering plates 24 boltedto the rails 3, the top edges of these plates being slightly higher than the rails. The flasks can be easily rolled onto the centering plates and thus positioned in alignment with the blow 4 'pipe 14.

With articular reference to Fig. II it will be seen t at the pipe casting 26 is of a standard ty e having a bell flange 28 at one end and a Bead-29 at the other end. The nozzle 25 isdirected into the mold 21 at the bead end of the casting.

The operation of the apparatus is as follows: When the flask 2 is positioned the car 10 is moved slightly forward so that the nozzle 25 barely penetrates the mold 21 midway between the inner surface of the flask 2 and the outer surface of the casting 26. The air valve is then opened, and a jet of air under considerable pressure is directed into the mold 21. The car 10 is then moved forward so that the blow pipe 14 is forced through the mold to a point adjacent the bell of the casting, blowing out the loosened sand at the end of the flask 2 corresponding to the bead end of the pipe casting and through the minute perforations 27. When the blow pipe has reached the limit of its travel, the block of sand between the nozzle 25 and the bell end of the casting is blown out and the bore is completed. It is found that by thus boring the mold, there is a suflicient disintegration and removal of sand to free the casting so that it can thereafter be readily removed by mechanical means. As long as the mold is intact, its cementitious property and the presence of the head on the end of the pipe casting prevent the extraction of the casting without danger of injury to flaskor casting. However, after boring the mold in the manner described, enough sand is removed from the annular space between flask and castin' and the disintegration of the mold is su ciently initiated, so that the later application of mechanical pressure tending to move the casting with respect to its flask will complete the disintegration of the mold and Within the contemplation of my invention. v

For ordinary purposes, however, I have found that a single application of an air jet will carry the disintegration of the'mold to such an extent as to permit the casting to be readily removed by the second step of the stri ping operation.

T e second step of the stripping operation preferably consists of subjecting the casting by mechanical appliances to a fflrce tending to move it inthe direction of its length while holding the flask stationary. For this purpose various forms of apparatus may be used, as for example, a hydraulic ram, or a-stripping apparatus comprising internal and external chucks applied to the casting and flask respectively and means for drawing the chucks apart. Such an apparatus is shown in United States Letters Patent-No. 1.758.883, granted to me on May 13, 1930.

. sand lining along one or more parallel-lines to provide a longitudinal slot so that, when a force is subsequently applied tending to move the pipe casting through the flask, the internal pressure normally caused by the bead tending to further compress the sand lining is relieved, there bein a space into which the sand particles may e forced permitting the distortion of the shape of the sand linin as the bead passes therethrough. According y, the preliminary boring operation makes it possible for a comparatively moderate force to' progress the casting through the flask without imposing undue strain upon flask or casting, and the power required to accomplish the disintegration of a sector of the sand lining and the extraction of the pipe is considerably less than that required to disintegrate the whole sand lining by successive annular increments. Furthermore, the apparatus herein described can obviously be employed for pipe castings of varying diameters and lengths without necessitating any change, and the equipment required for the'practice of my invention is inexpensive andof simple construction.

It will be apparent that While I- have referred to compressed air as the preferred medium for the preliminary disinte ration of the sand lining, other means for e ecting a longitudinal bore to slotthe sand lining throughout its length may be used in a similar manner to accomplish the same resultand the use of such other means is within the contemplation of this invention.

Having thus described my invention, I claim: I

1. The method of'extracting a casting from a cylindrical flask lined with a refractory mold which consists in slotting the mold longitudinally, and then separating the casting from its flask. 1

- 2. The method of extracting a casting from a cylindricalflack with an annular refractory linin which consists in disintegrating a sector o the annular lining by a pressure jet directed to effect a longitudinal bore within said lining, and then separating the casting from forcing the pressure jet through said lining nular sand lining which consists in directing a blow pipe into the end of the sand lining, forcing the blow pipe throughsaidsand lining while uiding the same in a arallel relation with t e axis of the flask w ereby the sand lining is slotted substantially throughout its length, and then separating the pipe casting from its flask.

5. The method of extracting a pipe casting from a cylindrical flask with an annular refractory lining which consists in slotting the refractory lining longitudinally by means of a pressure jet with removal of a sufiicient quantity of the refractory material to permit the pipe casting to be later progressed through the lining without further compressing the same, and then separating the casting from its flask.

6. The method of extracting a pipe casting having a head at one end and a bell at the other end from a cylindrical flask lined with a refractory mold which consists in directing means for delivering a pressure et into the refractory lining at the bead end of the casting, forcin said means longitudinall through the re ractory lining to a 'point a acent the I bell of the pipe casting whereby the lining is bored throughout its length, and then separating the casting from its flask.

7. The method of extracting a pipe casting having a bead at one end and a bell at the other end from a cylindrical flask lined-with a refractory mold which consists in directing a blow pipeinto' the refractory mold at the beadiend of the pipe casting, said blow pipe delivering a pressure jet, forcing said blow pipe through said mold whereby the mold is longitudinally bored to a point adjacent the bell of the pipe castin and a block of refractory material at the ell blown out at said end of the flask, and then separating the casting from its flask.

In testimony whereof, I have hereunto signed my name at Burlington, New Jersey, this 5th day of Se tember, 1929.

L UIS A. CAMEROTA.

while guiding the same in a parallel relation with the axis of the flask andthen separating the casting from its ask.

4. The method of extracting a pipe casting from a closed cylindrical flask with an an- 

